U.S. patent number 6,996,379 [Application Number 10/200,959] was granted by the patent office on 2006-02-07 for linear high powered integrated circuit transmitter.
This patent grant is currently assigned to Broadcom Corp.. Invention is credited to Shahla Khorram.
United States Patent |
6,996,379 |
Khorram |
February 7, 2006 |
Linear high powered integrated circuit transmitter
Abstract
A linear high powered integrated circuit transmitter includes an
up-conversion module, a plurality of power amplifiers, balanced
integrated circuit coupling, and a combining circuit. The
up-conversion module is operably coupled to produce a differential
up-converted signal by mixing one or more local oscillations with a
low intermediate frequency (IF) signal. The balanced integrated
circuit coupling couples the plurality of power amplifiers to the
up-conversion module such that the power amplifiers amplify the
up-converted signal to produce a plurality of amplified radio
frequency (RF) signals. The combining circuit is operably coupled
to combine the plurality of amplified RF signals to produce a
transmit RF signal.
Inventors: |
Khorram; Shahla (Los Angeles,
CA) |
Assignee: |
Broadcom Corp. (Irvine,
CA)
|
Family
ID: |
30769581 |
Appl.
No.: |
10/200,959 |
Filed: |
July 23, 2002 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20040198250 A1 |
Oct 7, 2004 |
|
Current U.S.
Class: |
455/91; 330/127;
455/114.3; 455/95 |
Current CPC
Class: |
H03F
3/45188 (20130101); H04B 1/406 (20130101) |
Current International
Class: |
H04B
1/02 (20060101) |
Field of
Search: |
;455/91,95,73,84,85,86,87,209,211,255,258,259,293,311,312,326,324,333,341 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Urban; Edward F.
Assistant Examiner: Nguyen; Thuan
Attorney, Agent or Firm: Garlick, Harrison & Markison,
LLP Markison; Timothy W.
Claims
What is claimed is:
1. A linear high-powered integrated circuit transmitter comprises:
up-conversion module operably coupled to produce a differential
up-converted signal by mixing at least one local oscillation with a
low intermediate frequency signal; a plurality of power amplifiers;
balanced integrated circuit coupling that couples the plurality of
power amplifiers to the up-conversion module, wherein the plurality
of power amplifiers amplify the up-converted signal to produce a
plurality of amplified radio frequency signals; and combining
circuit operably coupled to combine the plurality of amplified
radio frequency signals to produce a transmit radio frequency
signal.
2. The linear high-powered integrated circuit transmitter of claim
1, wherein the combining circuit further comprises: a plurality of
baluns operably coupled to the plurality of power amplifiers,
wherein the plurality of baluns converts differential signals into
a single-ended signals, wherein the plurality of power amplifiers
provides the plurality of amplified radio frequency signals as the
differential signals; and a combiner operably coupled to combine
the single-ended signals into the transmit radio frequency
signal.
3. The linear high-powered integrated circuit transmitter of claim
2, wherein each of the plurality of baluns further comprises at
least one of: a transformer balun; and an inductor-capacitor
circuit balun.
4. The linear high-powered integrated circuit transmitter of claim
2 further comprises: second balanced integrated circuit coupling
that couples the plurality of power amplifiers to the plurality of
baluns; and third balanced integrated circuit coupling that couples
the plurality of baluns to the combiner.
5. The linear high-powered integrated circuit transmitter of claim
1 further comprises: the plurality of power amplifiers provides the
plurality of amplified radio frequency signals as differential
current signals to the combining circuit; the combining circuit
includes directly coupling, a current to voltage circuit, and a
balun, wherein the direct coupling couples positive outputs of the
plurality of power amplifiers together to produce a positive
combined current signal and couples negative outputs of the
plurality of power amplifiers to produce a negative combined
current signal, wherein the current to voltage circuit converts the
first and second combined current signals into a differential
voltage signal, and wherein the balun converts the differential
voltage signal into the transmit radio frequency signal.
6. The linear high-powered integrated circuit transmitter of claim
1 further comprises being fabricated using CMOS technology.
7. A linear high-powered integrated circuit transmitter comprises:
up-conversion module operably coupled to produce a differential
up-converted signal by mixing at least one local oscillation with a
low intermediate frequency signal; a plurality of power amplifiers;
balanced integrated circuit coupling operable to coupled the
plurality of power amplifiers to the up-conversion module, wherein
the plurality of power amplifiers amplify the up-converted signal
to produce a plurality of differential amplified radio frequency
signals; and plurality of baluns operably coupled to the plurality
of power amplifiers, wherein the plurality of baluns converts the
plurality of differential amplified radio frequency signals into a
single-ended signals, and wherein the plurality of baluns provides
the single-ended signals off-chip for off-chip combining.
8. The linear high-powered integrated circuit transmitter of claim
7, wherein each of the plurality of baluns further comprises at
least one of: a transformer balun; and an inductor-capacitor
circuit balun.
9. The linear high-powered integrated circuit transmitter of claim
7 further comprises: second balanced integrated circuit coupling
that couples the plurality of power amplifiers to the plurality of
baluns; and third balanced integrated circuit coupling that couples
the plurality of baluns to pads for off-chip coupling to a
combiner.
10. The linear high-powered integrated circuit transmitter of claim
7 further comprises being fabricated using CMOS technology.
11. A linear high-powered integrated circuit transmitter comprises:
up-conversion module operably coupled to produce a differential
up-converted signal by mixing at least one local oscillation with a
low intermediate frequency signal; a plurality of power amplifiers;
balanced integrated circuit coupling that couples the plurality of
power amplifiers to the up-conversion module, wherein the plurality
of power amplifiers amplify the up-converted signal to produce
differential current signals; direct coupling that couples positive
outputs of the plurality of power amplifiers together to produce a
positive combined current signal and couples negative outputs of
the plurality of power amplifiers to produce a negative combined
current signal, current to voltage circuit operably coupled to
convert the positive and negative combined current signals into a
differential voltage signal, and a balun operably coupled to
convert the differential voltage signal into a single-ended
transmit radio frequency signal.
12. The linear high-powered integrated circuit transmitter of claim
11, wherein the balun further comprises at least one of: a
transformer balun; and an inductor-capacitor circuit balun.
13. The linear high-powered integrated circuit transmitter of claim
11 further comprises: second balanced integrated circuit coupling
that couples the plurality of power amplifiers to the current to
voltage circuit; and third balanced integrated circuit coupling
that couples the current to voltage circuit to the balun.
14. The linear high-powered integrated circuit transmitter of claim
11 further comprises being fabricated using CMOS technology.
Description
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
This invention relates generally to communication systems and more
particularly to radio transmitters used within such systems.
2. Description of Related Art
Communication systems are known to support wireless and wire lined
communications between wireless and/or wire lined communication
devices. Such communication systems range from national and/or
international cellular telephone systems to the Internet to
point-to-point in-home wireless networks. Each type of
communication system is constructed, and hence operates, in
accordance with one or more communication standards. For instance,
wireless communication systems may operate in accordance with one
or more standards including, but not limited to, IEEE 802.11,
Bluetooth, advanced mobile phone services (AMPS), digital AMPS,
global system for mobile communications (GSM), code division
multiple access (CDMA), local multi-point distribution systems
(LMDS), multi-channel-multi-point distribution systems (MMDS),
and/or variations thereof.
Depending on the type of wireless communication system, a wireless
communication device, such as a cellular telephone, two-way radio,
personal digital assistant (PDA), personal computer (PC), laptop
computer, home entertainment equipment, et cetera communicates
directly or indirectly with other wireless communication devices.
For direct communications (also known as point-to-point
communications), the participating wireless communication devices
tune their receivers and transmitters to the same channel or
channels (e.g., one of the plurality of radio frequency (RF)
carriers of the wireless communication system) and communicate over
that channel(s). For indirect wireless communications, each
wireless communication device communicates directly with an
associated base station (e.g., for cellular services) and/or an
associated access point (e.g., for an in-home or in-building
wireless network) via an assigned channel. To complete a
communication connection between the wireless communication
devices, the associated base stations and/or associated access
points communicate with each other directly, via a system
controller, via the public switch telephone network, via the
Internet, and/or via some other wide area network.
For each wireless communication device to participate in wireless
communications, it includes a built-in radio transceiver (i.e.,
receiver and transmitter) or is coupled to an associated radio
transceiver (e.g., a station for in-home and/or in-building
wireless communication networks, RF modem, etc.). As is known, the
receiver is coupled to the antenna and includes a low noise
amplifier, one or more intermediate frequency stages, a filtering
stage, and a data recovery stage. The low noise amplifier receives
inbound RF signals via the antenna and amplifies then. The one or
more intermediate frequency stages mix the amplified RF signals
with one or more local oscillations to convert the amplified RF
signal into baseband signals or intermediate frequency (IF)
signals. The filtering stage filters the baseband signals or the IF
signals to attenuate unwanted out of band signals to produce
filtered signals. The data recovery stage recovers raw data from
the filtered signals in accordance with the particular wireless
communication standard.
As is also known, the transmitter includes a data modulation stage,
one or more intermediate frequency stages, and a power amplifier.
The data modulation stage converts raw data into baseband signals
in accordance with a particular wireless communication standard.
The one or more intermediate frequency stages mix the baseband
signals with one or more local oscillations to produce RF signals.
The power amplifier amplifies the RF signals prior to transmission
via an antenna.
As an example, an integrated circuit transmitter implemented
utilizing 0.18.mu. CMOS technology, the maximum output power of a
power amplifier is approximately 7 dBm (dBm=10 log(power in
miliwatts). While this limited output power range is acceptable for
some applications, it is not acceptable for many of the newer radio
applications (such as IEEE 802.11a, b, Bluetooth, et cetera) that
require as much as 20 dBm of output power from the transmitter.
One solution to provide a greater output power is to use higher
performance integrated circuit process such as gallium arsenide or
silicon germanium. While these processes improve the output power,
they are significantly more expensive and thus limit their
applicability to produce in high-end communication equipment.
Another solution, which is more popular, is to use an off-chip
power amplifier. This solution provides greater power, but requires
additional integrated circuits and/or discrete components to
implement the power amplifier.
Therefore, a need exists for a CMOS based on-chip power amplifier
solution that provides a linear output response and that provides
output power greater than 7 dBm.
BRIEF SUMMARY OF THE INVENTION
The linear high powered integrated circuit transmitter of the
present invention substantially meets these needs and others. An
embodiment of a linear high powered integrated circuit transmitter
includes an up-conversion module, a plurality of power amplifiers,
balanced integrated circuit coupling, and a combining circuit. The
up-conversion module is operably coupled to produce a differential
up-converted signal by mixing one or more local oscillations with a
low intermediate frequency (IF) signal, which may have a carrier
frequency ranging from zero to a few mega-hertz. The low
intermediate frequency signal is representative of data that has
been modulated and/or encoded in accordance with a particular
communication standard and is being prepared for transmission. The
balanced integrated circuit coupling couples the plurality of power
amplifiers to the up-conversion module such that the power
amplifiers amplify the up-converted signal to produce a plurality
of amplified radio frequency (RF) signals. The balanced integrated
circuit coupling has substantially the same impedance and frequency
response characteristics between the up-conversion module and each
of the power amplifiers. The combining circuit is operably coupled
to combine the plurality of amplified RF signals to produce a
transmit RF signal.
Another embodiment of a linear high powered integrated circuit
transmitter includes an up-conversion module, a plurality of power
amplifiers, balanced integrated circuit coupling, and a plurality
of baluns. The up-conversion module is operably coupled to produce
a differential up-converted signal by mixing at least one local
oscillation with a low IF signal. The plurality of amplifiers are
coupled to the up-conversion module via the balanced integrated
circuit coupling and amplify the up-converted signal to produce a
plurality of differential amplified RF signals. The plurality of
baluns is operably coupled to the plurality of power amplifiers and
converts the plurality of differential amplified RF signals into
single ended RF signals. The plurality of single ended RF signals
is provided off-chip for off-chip combining or is provided to an
on-chip combiner.
Another embodiment of a linear high powered integrated circuit
transmitter of the present invention includes an up-conversion
module, plurality of power amplifiers, balanced integrated circuit
coupling, direct coupling, current-to-voltage circuit, and a balun.
The up-conversion module is operably coupled to produce a
differential up-converted signal by mixing at least one local
oscillation with a low IF signal. The balanced integrated circuit
coupling couples the plurality of amplifiers to the up-conversion
module. The plurality of amplifiers amplifies the up-converted
signal to produce a plurality of differential current signals. The
direct coupling couples positive outputs of the plurality of power
amplifiers together to produce a positive combined current signal
and couples negative outputs of the plurality of power amplifiers
to produce a negative combined current signal. The
current-to-voltage circuit is operably coupled to convert the
positive and negative combined current signals into a differential
voltage signal. The balun is operably coupled to convert the
differential voltage signal into a single ended transmit RF
signal.
In each of these transmitter embodiments, the plurality of power
amplifiers provides greater than 7 dBm of linear output power when
implemented as an integrated circuit using CMOS technology. For
example, by utilizing five power amplifiers in parallel, a linear
output power of approximately 20 dBm may be achieved.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
FIG. 1 is a schematic block diagram of a wireless communication
system in accordance with the present invention;
FIG. 2 is a schematic block diagram of a wireless communication
device in accordance with the present invention;
FIG. 3 is a schematic block diagram of a linear high powered
integrated circuit transmitter in accordance with the present
invention;
FIG. 4 is a schematic block diagram of an alternate embodiment of a
linear high powered integrated circuit transmitter in accordance
with the present invention; and
FIG. 5 is a schematic block diagram of yet another embodiment of a
linear high powered integrated circuit transmitter in accordance
with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic block diagram illustrating a communication
system 10 that includes a plurality of base stations and/or access
points 12 16, a plurality of wireless communication devices 18 32
and a network hardware component 34. The wireless communication
devices 18 32 may be laptop host computers 18 and 26, personal
digital assistant hosts 20 and 30, personal computer hosts 24 and
32 and/or cellular telephone hosts 22 and 28. The details of the
wireless communication devices will be described in greater detail
with reference to FIG. 2.
The base stations or access points 12 16 are operably coupled to
the network hardware 34 via local area network connections 36, 38
and 40. The network hardware 34, which may be a router, switch,
bridge, modem, system controller, et cetera provides a wide area
network connection 42 for the communication system 10. Each of the
base stations or access points 12 16 has an associated antenna or
antenna array to communicate with the wireless communication
devices in its area. Typically, the wireless communication devices
register with a particular base station or access point 12 14 to
receive services from the communication system 10. For direct
connections (i.e., point-to-point communications), wireless
communication devices communicate directly via an allocated
channel.
Typically, base stations are used for cellular telephone systems
and like-type systems, while access points are used for in-home or
in-building wireless networks. Regardless of the particular type of
communication system, each wireless communication device includes a
built-in radio and/or is coupled to a radio. The radio includes a
highly linear amplifier and/or programmable multi-stage amplifier
as disclosed herein to enhance performance, reduce costs, reduce
size, and/or enhance broadband applications.
FIG. 2 is a schematic block diagram illustrating a wireless
communication device that includes the host device 18 32 and an
associated radio 60. For cellular telephone hosts, the radio 60 is
a built-in component. For personal digital assistants hosts, laptop
hosts, and/or personal computer hosts, the radio 60 may be built-in
or an externally coupled component.
As illustrated, the host device 18 32 includes a processing module
50, memory 52, radio interface 54, input interface 58 and output
interface 56. The processing module 50 and memory 52 execute the
corresponding instructions that are typically done by the host
device. For example, for a cellular telephone host device, the
processing module 50 performs the corresponding communication
functions in accordance with a particular cellular telephone
standard.
The radio interface 54 allows data to be received from and sent to
the radio 60. For data received from the radio 60 (e.g., inbound
data), the radio interface 54 provides the data to the processing
module 50 for further processing and/or routing to the output
interface 56. The output interface 56 provides connectivity to an
output display device such as a display, monitor, speakers, et
cetera such that the received data may be displayed. The radio
interface 54 also provides data from the processing module 50 to
the radio 60. The processing module 50 may receive the outbound
data from an input device such as a keyboard, keypad, microphone,
et cetera via the input interface 58 or generate the data itself.
For data received via the input interface 58, the processing module
50 may perform a corresponding host function on the data and/or
route it to the radio 60 via the radio interface 54.
Radio 60 includes a host interface 62, digital receiver processing
module 64, an analog-to-digital converter 66, a
filtering/attenuation module 68, an IF mixing down conversion stage
70, a receiver filter 71, a low noise amplifier 72, a
transmitter/receiver switch 73, a local oscillation module 74,
memory 75, a digital transmitter processing module 76, a
digital-to-analog converter 78, a filtering/gain module 80, an IF
mixing up conversion stage 82, a power amplifier 84, a transmitter
filter module 85, and an antenna 86. The antenna 86 may be a single
antenna that is shared by the transmit and receive paths as
regulated by the Tx/Rx switch 73, or may include separate antennas
for the transmit path and receive path. The antenna implementation
will depend on the particular standard to which the wireless
communication device is compliant.
The digital receiver processing module 64 and the digital
transmitter processing module 76, in combination with operational
instructions stored in memory 75, execute digital receiver
functions and digital transmitter functions, respectively. The
digital receiver functions include, but are not limited to, digital
intermediate frequency to baseband conversion, demodulation,
constellation demapping, decoding, and/or descrambling. The digital
transmitter functions include, but are not limited to, scrambling,
encoding, constellation mapping, modulation, and/or digital
baseband to IF conversion. The digital receiver and transmitter
processing modules 64 and 76 may be implemented using a shared
processing device, individual processing devices, or a plurality of
processing devices. Such a processing device may be a
microprocessor, micro-controller, digital signal processor,
microcomputer, central processing unit, field programmable gate
array, programmable logic device, state machine, logic circuitry,
analog circuitry, digital circuitry, and/or any device that
manipulates signals (analog and/or digital) based on operational
instructions. The memory 75 may be a single memory device or a
plurality of memory devices. Such a memory device may be a
read-only memory, random access memory, volatile memory,
non-volatile memory, static memory, dynamic memory, flash memory,
and/or any device that stores digital information. Note that when
the processing module 64 and/or 76 implements one or more of its
functions via a state machine, analog circuitry, digital circuitry,
and/or logic circuitry, the memory storing the corresponding
operational instructions is embedded with the circuitry comprising
the state machine, analog circuitry, digital circuitry, and/or
logic circuitry.
In operation, the radio 60 receives outbound data 94 from the host
device via the host interface 62. The host interface 62 routes the
outbound data 94 to the digital transmitter processing module 76,
which processes the outbound data 94 in accordance with a
particular wireless communication standard (e.g., IEEE 802.11a,
IEEE 802.11b, Bluetooth, et cetera) to produce digital transmission
formatted data 96. The digital transmission formatted data 96 will
be a digital base-band signal or a digital low IF signal, where the
low IF typically will be in the frequency range of one hundred
kilohertz to a few megahertz.
The digital-to-analog converter 78 converts the digital
transmission formatted data 96 from the digital domain to the
analog domain. The filtering/gain module 80 filters and/or adjusts
the gain of the analog signal prior to providing it to the IF
mixing stage 82. The IF mixing stage 82 directly converts the
analog baseband or low IF signal into an RF signal based on a
transmitter local oscillation 83 provided by local oscillation
module 74. The power amplifier 84, which may be implemented in
accordance with the present invention, amplifies the RF signal to
produce outbound RF signal 98, which is filtered by the transmitter
filter module 85. The antenna 86 transmits the outbound RF signal
98 to a targeted device such as a base station, an access point
and/or another wireless communication device.
The radio 60 also receives an inbound RF signal 88 via the antenna
86, which was transmitted by a base station, an access point, or
another wireless communication device. The antenna 86 provides the
inbound RF signal 88 to the receiver filter module 71 via the Tx/Rx
switch 73, where the Rx filter 71 bandpass filters the inbound RF
signal 88. The Rx filter 71 provides the filtered RF signal to low
noise amplifier 72, which amplifies the signal 88 to produce an
amplified inbound RF signal. The low noise amplifier 72 provides
the amplified inbound RF signal to the IF mixing module 70, which
directly converts the amplified inbound RF signal into an inbound
low IF signal or baseband signal based on a receiver local
oscillation 81 provided by local oscillation module 74. The down
conversion module 70 provides the inbound low IF signal or baseband
signal to the filtering/gain module 68. The filtering/gain module
68 filters and/or gains the inbound low IF signal or the inbound
baseband signal to produce a filtered inbound signal.
The analog-to-digital converter 66 converts the filtered inbound
signal from the analog domain to the digital domain to produce
digital reception formatted data 90. The digital receiver
processing module 64 decodes, descrambles, demaps, and/or
demodulates the digital reception formatted data 90 to recapture
inbound data 92 in accordance with the particular wireless
communication standard being implemented by radio 60. The host
interface 62 provides the recaptured inbound data 92 to the host
device 18 32 via the radio interface 54.
As one of average skill in the art will appreciate, the wireless
communication device of FIG. 2 may be implemented using one or more
integrated circuits. For example, the host device may be
implemented on one integrated circuit, the digital receiver
processing module 64, the digital transmitter processing module 76
and memory 75 may be implemented on a second integrated circuit,
and the remaining components of the radio 60, less the antenna 86,
may be implemented on a third integrated circuit. As an alternate
example, the radio 60 may be implemented on a single integrated
circuit. As yet another example, the processing module 50 of the
host device and the digital receiver and transmitter processing
modules 64 and 76 may be a common processing device implemented on
a single integrated circuit. Further, the memory 52 and memory 75
may be implemented on a single integrated circuit and/or on the
same integrated circuit as the common processing modules of
processing module 50 and the digital receiver and transmitter
processing module 64 and 76.
FIG. 3 is a schematic block diagram of an embodiment of a linear
high powered integrated circuit transmitter 100 that may be used in
the wireless communication device illustrated in FIG. 2. The
transmitter 100 includes an up-conversion module 82, a plurality of
power amplifiers 84-1 through 84-3, a plurality of baluns 102 106
and a combining module 120. The transmitter 100 may be implemented
as an integrated circuit and may be fabricated in accordance with
CMOS technology, or any other type of integrated circuit
technology.
The up-conversion module 82 is operably coupled to mix a
differential low IF signal 108 with a differential transmit local
oscillation signal 83. The output conversion module 82 provides the
differential up-converted signal 110 to the plurality of power
amplifiers 84-1 through 84-3 via the balanced integrated circuit
coupling 112. The balanced integrated circuit coupling 112
constitute metal traces formed on one or more layers of the
integrated circuit and exhibit similar frequency response
characteristics and impedances such that the coupling between each
of the plurality of power amplifiers and the up-conversion module
is substantially identical.
Each of the power amplifiers 84-1 through 84-3 may be of a similar
construct, which includes a pair of input transistors to receive
opposite phases of the differential up-converted signal 110, loads
coupled in series with each of the input transistors and a current
source coupled to the sources of each transistor. As one of average
skill in the art will appreciate, the power amplifiers may be
constructed in a variety of ways to achieve the desired power
amplification.
Each of the power amplifiers amplifies the differential
up-converted signal 110 to produce a plurality of differential
amplified RF signals 114. Each of the differential amplified RF
signals 114 is provided to a corresponding balun 102 106. The
baluns 102 106, which may be transformer baluns or
inductor/capacitor baluns, convert the differential amplified RF
signals 114 into a plurality of single ended signals 116.
The combining module 120 receives the plurality of single ended
signals 116 and combines them to produce a single ended RF signal
118. The combining module 120 may be a power combiner, which is
commercially available, or a combination of passive components such
as inductors and/or capacitors. As one of average skill in the art
will appreciate, the combining module 120 may be an on-chip device
or an off-chip device. When the combining module 120 is on-chip,
the coupling between the baluns and the combining module 120 should
be balanced. Such balanced IC coupling provides similar impedances
and frequency responses between the baluns and combining module. If
the combining module 120 is off-chip, the balanced integrated
circuit coupling is between the baluns 102 106 and the
corresponding pins of the integrated circuit that includes
transmitter 100.
The transmitter 100 may further include the transmitter filtering
module 85 as illustrated in FIG. 2. Such a filtering module 85 may
be coupled to the output of the combining module 120.
Alternatively, the transmitter filtering module 85 may include a
plurality of differential filters coupled to the outputs of the
power amplifiers. As a further alternative, the transmitter
filtering module 85 may include a plurality of single-ended filters
coupled to the outputs of the baluns 102 106.
FIG. 4 is a schematic block diagram of another embodiment of a
linear high powered integrated circuit transmitter 130 which may be
used in the wireless communication device illustrated in FIG. 2.
The transmitter 130 includes the up-conversion module 82, the
plurality of power amplifiers 84-1 through 84-3, and a combining
circuit 132. The functionality, and construct, of the up-conversion
module 82, the balanced integrated circuit coupling 112 and the
power amplifiers 84-1 through 84-3 is as previously discussed with
reference to FIG. 3. The transmitter 130 may be implemented as an
integrated circuit and may be fabricated in accordance with CMOS
technology, or any other type of integrated circuit technology.
The combining circuit 132 receives the plurality of differential
amplified signals 114 from the power amplifiers 84-1 through 84-3.
Upon receiving these signals, the combining circuit 132 combines
them to produce a single ended RF signal 118. In one embodiment of
the combining circuit 132, it includes a plurality of baluns
operably coupled to the plurality of power amplifiers and a
combiner that combines the single ended signals produced by the
baluns.
The coupling between the power amplifiers and the combining circuit
132 is balanced such that the impedances and frequency/gain
responses of the coupling are balanced between each of the power
amplifiers in the combining circuit 132.
The transmitter 130 may further include the transmit filter 85 as
shown in FIG. 2 coupled after the combining circuit 132.
Alternatively, the transmit filter may include a plurality of
filters coupled to the outputs of the power amplifiers 84-1 through
84-3.
FIG. 5 is a schematic block diagram of another embodiment of a
linear high powered integrated transmitter 140 that may be used in
the wireless communication device illustrated in FIG. 2. The
transmitter 140 includes the up-conversion module 82, the balanced
integrated circuit coupling 112, a plurality of current mode power
amplifiers 84-A through 84-C, a current-to-voltage circuit 144, an
a balun 150. The transmitter 140 may be implemented as an
integrated circuit and may be fabricated in accordance with CMOS
technology, or any other type of integrated circuit technology.
In this embodiment, the up-conversion module 82 produces the
differential up-converted signal 110 by mixing the low IF signal
108 with the transmitter local oscillation 83. The power amplifiers
84-A through 84-C amplify the differential up-converted signal 110
and produces amplified current signals, which are differential. The
positive phases of each of the power amplifiers 84-A through 84-C
are directly coupled together via direct coupling 142 to produce a
positive combined current signal 146. Similarly, the negative
phases of the power amplifier output 84-A through 84-C are directly
combined via direct coupling 142 to produce a negative combined
current signal 148. Accordingly, the power amplifiers 84-A through
84-C are transconductance power amplifiers.
The current-to-voltage circuit 144 converts the positive and
negative combined current signals 146 and 148 into a differential
voltage signal. The current-to-voltage circuit 144 may include
resistors, inductors, capacitors and/or transistors to perform the
current-to-voltage transformation. The balun 150, which may be a
transformer or inductor/capacitor circuit, receives the
differential voltage and converts it into a single ended RF signal
118. The transmit filter 85 as shown in FIG. 2 may be included
before or after the balun 150.
The preceding discussion has presented various embodiments of a
linear high powered integrated circuit transmitter that may be
implemented using CMOS technology to achieve linear output power
ranges greater than 7 dB. While the embodiments of FIGS. 3 5 have
shown three power amplifiers, more or less amplifiers may be used
to achieve more or less output power than the approximately 13 dBm
provided by three power amplifiers. As one of average skill in the
art will appreciate, other embodiments may be derived from the
teaching of the present invention, without deviating from the scope
of the claims.
* * * * *